The Chemistry of Life

Cornell NotesCornell Notes

The Chemistry of Life

What are things made of?

Chemistry changes the way you look at the world.

The Chemistry of Life

What is ChemistryWhat is Chemistry

Chemistry - is the study of the structure, properties, and composition of substances, and the and the changes that substances undergoes

In Your Room

•Everything you can see, touch, smell or taste in your room is made of matter.

What Is Matter?• Matter is defined as

anything that occupies space and has mass.

• Matter is actually composed of a lot of tiny little pieces we call atoms that make up Elements.

Everything is made up of elements

The Chemistry of LifeElements

ElementsThe Chemistry of Life

EVERYTHING is made up of substances called elements

EVERYTHING can be broken down to the simplest parts called elements

Element – substance that cannot be broken down into simpler chemical substances (gold, Silver, Carbon)

Hydrogen

The Chemistry of Life

Element Symbol

Atomic Mass(protons+ electrons+ neutrons)

Atomic Number (# Electrons or Protons)

Trace elementsThe Chemistry of Life

Elements make up all things, Elements make up all things, including living things.including living things.

Some are present in very Some are present in very small amounts in living things. small amounts in living things. These are known as These are known as trace trace elementselements..

BrainPOP: Atoms

AtomsThe Chemistry of Life

Smallest particle of an element

basic building blocks of all elements

structure is crucial to identification

Atoms are the building blocks of all elements

Hydrogen Nitrogen

Oxygen

Carbon

Proton Neutron

Electron

The Chemistry of Life

AtomsThe Chemistry of Life

Atoms have a nucleus that contains protons and neutrons

Electrons fly around the nucleus in “shells” (energy levels)

PROTON – Positive Charge

NEUTRON – No Charge

ELECTRON – Negative Charge

Electron Energy Levels

• The 1st shell can hold up to 2 valence e-.

• The 2nd shell can hold up to 8 valence e-.

• The 3rd shell can hold up to 8 valence e-.

The numbers•The large number one in the upper left hand corner is the atomic number. It is the number of protons.

The numbers•The number on the bottom is the atomic mass number. It is also known as the molar mass, or atomic weight. It is the number of protons + the number of neutrons, (when you round it to the nearest whole number).

Isotopes

•Atoms of the same element by definition have the same number of protons.•Atoms of the same element that contain different numbers of neutrons are called isotopes of each other.

Compounds •a substance that is composed of two or more atoms of different elements

Bonds

• There two types of bonds:• a. covalent• b. ionic

Covalent bonds•Covalent bonds occur when atoms share electrons.

Ionic Bonds•Ions are atoms with a charge. They have a charge due to an imbalance in the number of protons and neutron.•The attractive force between two ions of opposite charges is known as an ionic bond.

Quick terms

• metabolism = all of the chemical reactions that take place within an organism

• mixture = a combination of substances in which the individual components retain their properties

• solution = a mixture in which one or more substances (solutes) are distributed evenly in another substance (solvent)

pH scale •pH is the measure of how acidic or basic a solution is.•acids netural bases

Properties of H2O•it is polar•it can form hydrogen bonds with other molecules•it can experiences capillary action•it resists temperature change•it expands when it freezes

Polar Molecules•Water is polar because the electrons spend more time around the oxygen atom, giving it a partial negative charge and consequently giving the hydrogen atoms partially positive charges.

Hydrogen Bonding•The attraction between opposite charges between hydrogen and oxygen forms a weak bond called a hydrogen bond.

Capillary Action…•is the ability of water to crawl up thin tubes.•This property makes it possible for water to get from roots in the ground to the leaves of the tallest trees.

Diffusion•is the net movement of particles from an area of higher concentration to an area of lower concentration. This occurs due to the random movement of particles known as Brownian motion

Diffusion

• Happens automatically• Particles spread out until

evenly spaced• They move in straight lines

and collide • Motion continues forever

Brownian Movement• atoms do not just stand still in liquids,

solids, and gases• atoms actually move around randomly• atoms can also bump into each other• the random bumping into each other is

called Brownian Movement

Diffusion• the movement of atoms from one area of

high concentration to an area of low concentration

• particles want to even out

Equilibrium

• Even distribution of molecules has been reached

• No “net” change in system, but molecules are still moving

•Imagine the particles are perfume molecules trapped inside a bottle. Remove the lid of the bottle by pressing the button and watch the perfume molecules diffuse throughout the room.

3 Key Factors to Diffusion

• Temperature• Concentration• Pressure

Life Substances•Carbon is the most important molecule to life on Earth.•This is due to the fact that it can form up to four bonds.•Because of this fact carbon can form many different shaped molecules, even using the same atoms.•Glucose and Fructose are isomers of each other.

Variations•Because of this fact carbon can form many different shaped molecules, even using the same atoms.•Glucose and Fructose are isomers of each other.

Polymers•When smaller molecules bond together they form long molecules called polymers.•Glucose and fructose bond together to form sucrose.

4 major macromolecules•carbohydrates•lipids•proteins•nucleic acids

Carbohydrates•are composed of carbon, hydrogen and oxygen.•1C: 2H :1O

•CxH2xOx

•These are basically sugars: mono-, di- and poly- saccharides

Lipids•are composed mostly of carbon and hydrogen with a small amount of oxygen•Fats, oils, waxes and steroids are all lipids.•They are non-polar and so don’t mix with water.

•

Proteins•A protein is a large complex polymer composed of carbon, hydrogen, oxygen, nitrogen and sometimes sulfur.•Two or more amino acids held together by a peptide bonds are considered a protein.

Special Proteins•Enzymes are proteins that change the rates of chemical reactions. they are necessary for life as we know it.

Nucleic acids… •are complex biomolecules that store cellular information in the form of a code.•They are polymers made up of subunits called nucleotides.